Electromagnetic device



June 10, 1930. ,1. R. FRY 1,762,774

ELECTROMAGNETIC DEVICE Filed June 15, 1928 /7 .z/ 750 7 5 7 I 7 M 22 E N 5 I i I N /Z 75 0 FIG 3 56.4

/NVENTO/? #005 H. FRY 5) ATTORNEY Patented June 10, 1930 UNIT "D STATES JACOB R. FRY, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TO BELL TELEPHONE LABORA- TOBIES, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK ELECTROMAGNETIC DEVICE Application filed June 15,

This invention relates to electromagnetic devices and particularly to devices employed for measuring purposes.

The object of the invention isto increase the sensitivity of these devices.

Suggestions have been made heretofore to measure the service rendered a telephone subscriber by means of a substation meter comprising a disc immersed in a mercury bath and rotating continuously, during conversatlon on the line, due to magnetic action on the disc resulting from the flow of the talking current therethrough. In these prior devices only a portion of the disc is in operative relation to the pole pieces of the magnets at any given time. Moreover, only a portion of the current reaches the disc due to the shunting eiiect of the mercury and of this portion only a part passes beneath the pole pieces of the magnets with the result that a fractional part of the total current is effective in producing torque.

According to the present invention the sensitivity of these devices is increased by pro- 5 viding a construction in which the operating current is so directed that all of it flows through the rotating disc at points in proximity to the poles of the magnets. In this way the torque necessary to drive the meter gear train is produced with smaller values of operating current.

In the drawing Fig. 1 is a sectional view taken vertically through the center of the de vice and illustrating the internal construction. Fig. 2 is a section taken along the horizontal plane indicated at 2-2 in Fig. 1. Fig. 3 is a side view of one of the permanent magnets. Fig. 4 is another view of the permanent magnet taken at right angles to the one shown in Fig. 3.

The device herein described is particularly suitable for use at the substations of telephone lines for measuring the length of conversation. In principle, it comprises a movable element which rotates continuously in response to the flow of current in the telephone line during the conversational period. Since the intensity of the current in a subscribers line is of a low order, the problem of designing 3 device which will produce sufficient mecham 1928. Serial No. 285,519.

ical energy to operate a recording instrument is a difficult one. To meet this difliculty the device herein described is so constructed that the entire amount of current available in the subscribers line is conducted through the rotatable element or disc in such a way that the current flowing through the disc passes in close proximity to the pole pieces of the statlonary permanent magnets, whereby the maximum amount of turning effort is produced.

Referring to the drawing, the measuring device comprises two stationary cup-shaped permanent magnets 1 and 2 as illustrated in Fig. 1. The magnet, which is further illustrated in Figs. 3 and 4, is a circular shaped member having an outer annular wall 3 and an integral cylindrically shaped portion 4. The portion 4 has a cylindrical orifice passing therethrough for the purpose of admitting a spindle. Except for the orifice in the portion 4, the other permanent magnet 2 is a counterpart of the first, having its outer annular wall 5 and its inner cylindrical portion 6. The permanent magnet 1 is so magnetized that the annular wall 3 constitutes one pole piece and the cylindrical portion 4 the opposite pole piece, the return path being by way of the solid or base portion of the member. Similarly the magnet 2 is magnetized such that the wall 5 is one pole piece and the inner element 6 the opposite pole piece.

hen the device is assembled as illustrated in Fig. 1, the magnets 1 and 2 are placed in opposing relation. The poles are so related to each other that a field of force exists in the continuous circular air gap formed by the opposing faces of the walls 3 and 5.

Surrounding the magnets 1 and 2 near their pole tips is an insulating member '7 so shaped as to provide a closed chamber within. The lower portion of the insulating member 7 is provided with an annular channel 8, passing around the outer portion of the insulating member '7 The lower part is also provided with a second annular channel 9 of smaller diameter and concentric with the first. The channels 8 and 9 contain some conducting fluid such as mercury.

A. rotatable disc 10, which. may be of some 7 the chamber formed by the insulating member 7. The disclO has two concentric continuous flanges 11 and 12 so positioned on the underside of the disc that when the instrument is assembled these flanges are immersed in the mercury filling the channels 8 and 9 respectively.

The spindle 13 passes through the orifice in the magnet 1 and is. delicately pivoted as seen in Fig. 1. The external part of the spindle 13 is pivoted in the stationary member 24 and carries a driving wheel or sprocket 25. The sprocket 25 engages other Wheels 26,27 and 2.8 whichconstitute the Well-known measuring train.

In order that the operating current may be conducted through the instrument, the conductorsl l and15 are connected to the mercury channels as illustrated. The conductor 14, for example, appears in terminals 1 6, 17 18 and 19,-Which are secured in the edge of thechannel 8 in physical contact with the mercury therein. Likewise theronductor 15 is multiplied tothe terminals 20, 21,22 and 23 located in the edge or" the channel 9.

Considering the conductors ll and 1 5 connected in series with a telephone line, as an instance of the utility of this device, a brief description will now be given of the operation. Current flowing into theinstrument over conductor 14. passes to the terminals 16, 17, 18 and 19 at equally spaced points around the circumference of the device. From these points it enters the mercuryv in the channel. 8 and passes directly to the disc by way'ot the flange 11. After reaching the flange 11 the current passes radially through the disc 10 under the pole pieces of the permanent magnet and thence through the flange 12 into the mercury in the channel 9 and thence tothe terminals 20, 21, 22

and 23. to the return conductor 15. The current flowing. directly through, the held of the permanent magnet produces, in the Well known manner, a turning effort which causes the discv 10 to rotate. Thus the rotation of the. disc is a measure, of thelen-gth of; time during which current flows in. the circuit andmay be taken as a measure of the length of a telephone, conversation.

While only ,oneembodiment of. the invention has been illustrated it will be; understood that numerous modifications may, be nadeand also that the instrument is, not

initedto use in telephonesystems, but may Me employed fora Variety of purposes.

What is claimed. is:

1.. combination, a magnet having an annular pole piece, a rotatable disc arranged in continuous magnetic. relation with said pole piece, and means for directing a flow of current across said: disc atdijiferentpoints a eu t umf ren e 'my name this 12th day.

2. In combination, a cup-shaped permanent magnet having a central pole piece and a continuous peripheral pole piece, a rotatable disc arranged in continuous magnetic relation with said peripheral pole piece, and means for directing a flow of current through said disc at predetermined points in proximity to said peripheral pole piece. I

3. In combination, two cup-shaped permanent ag e with t nu sr l pieces. a rotatable current conducting member supported for rotation between said pole pieces, and. an. electric circuit for directing a How of current through said member at definite aoints under said pole pieces.

4. The combination in a metering device of a magnet havinga continuouscircular pole piece, a disc supported for rotation in proximity to said pole piece, a member containing a current conducting liquid through which said disc rotates, and an electric circuit including said liquid'for directing a f w f termined points. I

5. The combination in a metering device of a magnet having a continuous circular pole piece, a disc supported for'rotation in proximity tosaid pole piece, amember having annular channels filled with. mercury,said disc having portions immersed in. said mercury during its rotation, and electric circuit current through said disc at: pre detinuous circular pole piece,a-disc supported 7 on a spindle for rotation. in proximity to said pole piece, means for directing a flowoi current through the disc at predetermined radial points, and a registering device driven by said spindle. i i V In witness whereof, I hereunto. subscribe of June, 1928. i

B FRY. 

